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<head>
  <meta charset="UTF-8">
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  <title>Document</title>
</head>

<body>
  <script>
    function array(a) {
      let arr = a.split("")
      let res = 0;
      let count = 0
      for (let i = 0; i < arr.length; i++) {
        if (arr[i] == 'L') {
          count++
        }
        if (arr[i] == 'R') {
          count--
        }
        if (count == 0) {
          res++
        }
      }
      return res
    }
    console.log(array("RLRRRLLRLL"))

  </script>
</body>

</html>